1. Weathering, Erosion, and Deposition

2. Weathering, erosion, and deposition changes the Earth’s surface
Weathering-wears down the Earth’s surface
Erosion-moves the Earth’s surface (acts as a bridge between the weathering and deposition)
Deposition-builds up the earth’s surface

3. Weathering
Processes at or near Earth’s surface that cause rocks and minerals to break down
Mechanical – Processes that break a rock or mineral into smaller pieces without altering its composition
Chemical – Chemically breaking down rock into new substances

4. Types of Mechanical
Abrasion - grinding and wearing down of rock surfaces by other rock or sand particles, usually rounded. Happens by wind, water, and gravity
Ice Wedging – Freezing and expansion of water within rock cracks.
Exfoliation – Peeling back of rock layers

5. Mechanical Continued Biotic Weathering
Plants – Send roots into small cracks in rock, the force of the growing roots cracks the rock even more, eventually breaking the rock down.
Animals – Animals dig through the soil and move soil particles around, exposing fresh surfaces

6. Abrasion
Wind Abrasion

7. Ice Wedging

8. Exfoliation

9. Biotic Weathering
Plant Weathering
Animal Weathering

10. Types of Chemical Weathering
Acid Rain – Precipitation containing acids because of pollution in the air
Oxidation – Chemical reaction in which an element, such as iron, combines with oxygen to form an oxide. Copper Penny
Acid in Ground Water – Some water contains weak acids which over long periods of time dissolve rock forming large caverns (not all caverns)

11. Acid Rain
The rock at Moon Valley has been worn away unevenly by decades of acid rain

12. Oxidation

13. Acid in groundwater

14. Erosion
Erosion is simply movement down a slope due to gravity. We call it erosion if the rock particle is moved by some flowing agent such as air, water or ice.
Erosion creates Valleys, Plateaus, Saddles
So, here it is: if a particle is loosened, chemically or mechanically, but stays put, call it weathering. Once the particle starts moving, call it erosion.

15. Glaciers

16. Water
Galveston before and after IKE

17. Wind

18. Deposition
The process of eroded earth materials (sediments) being deposited in a new location
Ex: delta-where sediment is deposited where a river flows into an ocean or lake builds up a landform
Ex: sand dune-a deposit of wind blown sand

19. Delta’s

20. Sand Dunes